1. Field of the Invention
The present invention relates generally to apparatus for controlling automobile air-conditioners, and more particularly to an apparatus for controlling the operation of an automobile air-conditioner so as to condition air in the vehicle passenger compartment with adequate consideration for the influence of solar radiation.
2. Description of the Prior Art
Typical examples of such automobile air-conditioner controlling apparatus are disclosed in Japanese Utility Model Laid-open Publication No. 59-80109 and Japanese Patent Publication No. 62-5085. The disclosed control apparatus includes four solar radiation sensors disposed adjacent to four corners in a vehicle passenger compartment for detecting the direction and quantity of solar radiation which are in turn used to control the position of an air-distributing door for canceling out the influence of solar radiation, thereby eliminating uneven temperature distribution in the vehicle passenger compartment.
As shown in Japanese Patent Laid-open Publication No. 59-34915, a control signal which is used for controlling the temperature of the vehicle passenger compartment is obtained by modifying the waveform of a solar radiation quantity detection pulse signal in such a manner that leading and trailing edge portions of the pulse signal progressively rises and lowers, respectively. With this waveform modification, the vehicle compartment temperature varies gently and smoothly and hence the occupant feels a sense of natural air-conditioning.
However, when such waveform-modified solar radiation quantity detection signal is used to calculate the direction of solar radiation for controlling the position of the air-distributing door, the resulting air-distribution control is incapable of follow up changes in the solar radiating direction. This is because the direction of solar radiation changes frequently depending on a traveling environment of the automobile. In this instance, if the solar radiation quantity detection signal changes progressively in the process of calculation of the solar radiating direction, the presence and absence of the solar radiation cannot be followed by the actual air-conditioning with the result that a great temperature difference is produced in the vehicle passenger compartment.